Manufacturing valve balls



06L 1967 A. L. FREEBORN 3,348,398

MANUFACTURING VALVE BALLS Filed Feb. 20, 1964 2 Sheets-Sheet 1 INVENTOR ANDREW L FREEBORN BY Mbm ATTORNEY Oct. 24, 1967 Filed Feb. 20, 1964 A. L. F'REEBORN MANUFACTURING VALVE BALLS 2 Sheets-Sheet 2 United States Patent 3,348,398 MANUFACTURING VALVE BALLS Andrew L. Freeborn, Hayesville, Ohio, assignor to The Ohio Brass Company, Mansfield, Ohio, a corporation of New Jersey Filed Feb. 20, 1964, Ser. No. 346,256 6 Claims. (Cl. 7280) This invention relates to metal finishing and concerns particularly the manufacture of spherical valve elements for ball valves.

An object of the invention is to provide improved methods and apparatus for finishing and surface hardening or burnishing spherical blanks.

Other and further objects, features and advantages of the invention will become apparent as the description proceeds.

In carrying out the invention in accordance with a preferred form thereof, a spherical metallic blank is finished by mounting the spherical blank upon a spindle which is turned at some predetermined slow speed. While so turned, the exterior surface of the spherical blank is contacted by the cylindrical surfaces of rolls, for example three rolls, which are carried in vertically inclined and circumferentially spaced relation on a rotating head. The head is carried in the chuck of a rotating drive such as that of a drilling machine which has a rotation axis perpendicular to and intersecting the axis of the spindle which carries the spherical blank. Pressure of the rolls upon the exterior of the blank works the surface metal of the blank into a smoothed and hardened surface.

A better understanding of the invention will be afforded by the following detailed description considered in conjunction with the accompanying drawing in which:

FIG. 1 is an end view in elevation of apparatus which may be employed for carrying out the finishing method.

FIG. 2 is a view as seen from the bottom of the rotating roll-carrying head of the apparatus of FIG. 1;

FIG. 3 is a view of a longitudinal section of the apparatus of FIG. 1 represented as cut by a vertical plane; and v FIG. 4 is a view of the apparatus of FIGS. 1 and 3 as seen from the bottom.

As best shown in FIGS. 1 and 3 of the drawing, a spherical blank 11 is surface finished by slowly rotating it while applying pressure progressively to successive points in the periphery of a small circle on the surface of the blank. The path of application of pressure is represented in FIGS. 1 and 3 by the small circle 12. The pressure may be applied in any suitable manner as by means of rolls 13. The rolls 13 are pressed against the surface of the ball blank 11 and rolled over the surface along the small circle 12. By causing the ball blank 11 to be rotated slowly at the same time with a peripheral speed a fraction of the peripheral speed of the roll 13 reasonable overlays on successive passes of the finishing rolls are accomplished.

Suitable apparatus for carrying out the method of the invention is illustrated in the drawings. Mounted upon a base 14 is a bearing block 15 which may be secured in any suitable manner as by means of welds 16 to the base 14. Within the bearing block 15 is a ball bearing unit 17 carrying a journal 18. A sheave 19 is secured to the journal 18 in any suitable manner, for example by a threaded joint represented by mating threads 21 and a lock washer 22 having a spur 23 splined in a longitudinal groove 24 formed in the threaded outer surface of the journal 18. A groove 25 is formed in the sheave 19 to receive a belt 26, driven by suitable means, not shown, for producing slow rotation of the journal 18. v

At one end of the journal 18 a suitable chuck is formed for supporting the ball blank 11. When the ball blanks 3,348,398 Patented Oct. 24, 1967 "ice 11 are in the form of valve elements or other blanks having a hollow cylindrical interior with a cylindrical surface 27, the supporting chuck takes the form of a split flexible expanding cylinder 28 with a plurality of horizontally extending grooves 29 cut therein as illustrated in FIG. 1. The cylinder 28 is formed with a tapering or conical bore to receive an expander 31 with means for moving it axially to expand the surface of the cylinder chuck 28 against the inner cylindrical surface 27 of the blank 11 and thereby secure it.

In the apparatus illustrated the tapering expander 31 is provided with a shank 32 extending through the journal 18, which is hollow, and provided with a threaded opposite end 33 cooperating with a knurled nut 34 adapted to bear against the right hand end 35 of the journal 18 for drawing in the tapering expander 31 to secure the chuck cylinder 28.

The roll means 13, preferably constituting a plurality of rolls such as the three rolls shown in the drawing, are mounted in a rotating head 36 with axes of rotation oblique to and intersecting the axis of rotation of the head 36. Preferably the rolls 13 are arranged symmetrically around the axis of rotation of the head 36 to avoid unbalance in the side thrust of the reaction pressure upon the head 36. Any suitable means for mounting therolls 13 may be provided such for example as round head machine screws 37 threaded into the head 36 to form spindles carrying ball bearings 38.

The ball bearings 38 include inner races 39 secured by the spindles 37 and outer races which constitute the rolls 13 bearing upon the surface of the spherical blank 11. It will be understood that the end 41 of the rotating head 36 is countersunk in order that it will clear the surface of the spherical blank 11.

Any suitable means may be provided for rotating the head 36. For example, in the arrangement illustrated with the blank carrying journal 18 rotating around a horizontal axis, a vertical drill press or drilling machine, not shown, having a chuck 42 may be provided to receive the rotating head 36. In this case the head 36 is provided with a suitable shank 43 adapted to the form of chuck 42 employed in the drilling machine.

The driving mechanism for the drilling machine is not shown. Preferably, however, it is so adjusted as to cause the chuck 42 to rotate a plurality of times for each rotation of the blank 11 with the rotating journal 18. Speeds are not critical but overlays on successive passes of the rolls 13 are desired. Satisfactory results have been accomplished in the finishing and surface hardening of brass balls for valves with the blank spindle or journal 18 rotating about 2 revolutions per minute and the head 36 rotating about 400 revolutions per minute. In this manner brass valve balls have been manufactured with a reduction in diameter from the blank of .0005 inch on a 1 /1 inch brass ball. The surface hardness increased from 22 Rockwell b to 88 Rockwell b in the finished ball. The completed ball had a 15 microinch RMS surface finish.

Pressure of the rolls 13 upon the exterior of the blank 11 works the surface metal of the blank into a smooth and hardened surface. The spherical blank is originally formed in any desired manner as by machine rough stock, casting or otherwise.

It is important that substantial plastic modification of the surface of the spherical blank is accomplished with relatively low pressures exerted upon the head 36. Accordingly, the method is useful for surface hardening and for finishing spherical metal parts generally. It will be understood that the speed of the head 36 will be determined in part by the material of the work piece, the pressure to be exerted by the head 36, and that the speed of the journal 18 is related to those factors. A considerable 3 V range of speeds and pressures may be utilized, depending upon the finish required.

While the invention has been described as embodied in concrete form and as operating in a specific manner in accordance with the provisions of the patent statutes, it should be understood that the invention is not limited thereto, since various modifications will suggest themselves to those skilled in the art without departing from the spirit of the invention. 7

I claim: 7

1. Ball surface finishing apparatus comprising in combination a split expansible chuck adapted to fit within a cylindrical opening in the interior of a spherical ball blank to be finished, means for expanding the chuck to secure a ball blank thereon, means for rotating the chuck, a rotatable head having a rotation axis substantially perpendicular to the rotation axis of the chuck and a plurality of mutually opposed rollers rotatably mounted upon the head, each having an axis of rotation inclined relative to the axis of rotation of the head and intersecting the rotation axis of the head at an angle less than 90 de-' grees thereto, whereby the roller peripheries contact simultaneously a ball blank carried by the ball-holding chuck and move along a circular path over the surface of the blank.

' 2. Apparatus for finishing ball blanks comprising in combination a chuck for receiving a spherical ball blank over the exterior thereof and means for securing the blank on the chuck, means rotatably supporting the chuck, a rotatable member having an axis intersecting the rotation axis of the first mentioned chuck, a plurality of roller means mounted upon said rotatable member for rotation on axes inclined to the rotation axis of the rotatable member and having mutually opposed, peripheral surfaces adapted to contact the surface of a ball blank perpendicular to diametral axes thereof carried by the first mentioned rotatable chuck, and means for rotatably driving the rotatable member at a speed in excess of the speed of rotation of the chuck.

3. That method of finishing a previously formed solid spherical blank, to smooth and harden the surface thereof, which comprises supporting the previously formed blank on a first diametric axis thereof, contacting the blank with a plurality of rolls having the faces thereof directed tangentially to the surface of the blank and perpendicular to diametric axes at the points of contact thereof, moving the rolls along a circular path having a diameter less than the diameter of the blank and defined by a central axis of rotation directed centrally through the blank, and turning the blank on the first diametric axis to contact the rolls along successive circular arcs for progressive plastic modification of the surface thereof.

4. That method in accordance with claim 3, in which the blank has a cylindric opening defining the first diametric axis, and the central axis of the circular path defines a second diametric axis directed substantially perpendicular to the first diametric axis.

' 5. That method of finishing a previously formed solid spherical blank, to smooth and harden the surface thereof, which comprises supporting the previously formed blank on a first diametric axis thereof, contacting the blank with a plurality of mutually opposed cylindric rolls having the faces thereof directed tangentially to the surface of the blank and perpendicular to diametric axes at the points of contact thereof, moving the rolls along a circular path about a second diametric axis directed substantially perpendicularly to the said first diametric axis and mm trally through the blank, the said rolls being pressed against the blank to reduce the diameter of the blank by a progressive plastic modification of the surface thereof,

of the rolls about the second diametric axis is large relative to the rate of rotation of the blank about the first diametric axis.

' References Cited UNITED STATES PATENTS 1,922,087 8/ 1933 Hiester 72-115 2,408,596 10/1946 Bednar et al 72-80 3,221,527 12/ 1965 Roehrs 72-80 CHARLES W. LANHAM, Primary Examiner.

L. A. LARSON, Assistant Examiner. 

3. THAT METHOD OF FINISHING A PREVIOUSLY FORMED SOLID SPHERICAL BLANK, TO SMOOTH AND HARDEN THE SURFACE THEREOF, WHICH COMPRISES SUPPORTING THE PREVIOUSLY FORMED BLANK ON A FIRST DIAMETRIC AXIS THEREOF, CONTACTING THE BLANK WITH A PLURALITY OF ROLLS HAVING THE FACES THEREOF DIRECTED TANGENTIALLY TO THE SURFACE OF THE BLANK AND PERPENDICULAR TO DIAMETRIC AXES AT THE POINTS OF CONTACT THEREOF, MOVING THE ROLLS ALONG A CIRCULAR PATH HAVING A DIAMETER LESS THAN THE DIAMETER OF THE BLANK AND DEFINED BY A CENTRAL AXIS OF ROTATION DIRECTED CENTRALLY THROUGH THE BLANK, AND TURNING THE BLANK ON THE FIRST DIAMETRIC AXIS TO CONTACT THE ROLLS ALONG SUCCESSIVE CIRCULAR ARCS FOR PROGRESSIVE PLASTIC MODIFICATION OF THE SURFACE THEREOF. 